The combination of phase transformation of zirconia and plastic deformation of Ni metal has shown a significant improvement in toughness caused by the synergistic toughening. In the present study, the reduction process within a carbon bed, the effect of Ni content on densification, microstructure and mechanical properties of ZTA/Ni composites was investigated. Powder mixtures of Al2O3, 3YSZ, and nickel nitrate as a source of Ni metal were prepared by precipitated Ni on ceramic powders to obtained ZTA/Ni composites. The composites were pressureless sintered at 1600 oC for 3 hrs within a carbon powder bed. The results showed that the addition of 5 vol.% Ni results in the highest relative density of 93% and the maximum fracture strength and toughness values of 348MPa and 3.32 MPa.m½, respectively.

Keywords: Multiphase Synergistic toughening, ZTA/Ni composites, carbon powder bed